Software developers have won back the right to patent programs in Britain, but only in strictly limited circumstances.
The change follows a successful appeal by software developers against the UK Intellectual Property Office's (UK-IPO) former practice of denying patent protection to all computer programs.
Last week UK-IPO issued a Practice Notice that sets out the changes.
Andrew Bartlett, deputy director of UK-IPO, said the change brings the UK more into line with the rest of Europe.
For example, in the past the program for the microprocessor that controlled a patentable anti-braking system for motor vehicles was excluded, he said. The manufacturers can now claim patent protection for the program itself as well as the whole system.
Other examples of software that might be patentable could be process control programs or programs that controlled DNA sequencing systems, provided the algorithm performed by the program is patentable, Bartlett said.
However, he did not expect a flood of new applications. Generic programs such as word processors and spreadsheets were still not patentable, he said.
The change follows a court challenge to UK-IPO practice that followed a judgment in November 2006 in the cases of Aerotel Ltd v Telco Holdings Ltd (and others) and Macrossan's Application  RPC 7 ("Aerotel/Macrossan"). In these cases, "the Court of Appeal reinterpreted the law on patentable subject matter in the field of computer-implemented inventions," the UK-IPO said.
At the time, the UK-IPO said that patent claims for computer programs or for embedded programs were not allowable.
A group of patent applicants jointly challenged the change in practice. They argued that if their programmed alogorithms and equipment were patentable, they should also be able to protect the underlying computer programs themselves. This challenge led to a hearing before Mr Justice Kitchin in the High Court (Astron Clinica's Application and others Applications  EWHC 85 (Pat).
"In his judgment, Kitchin J has now clarified the law in this area, and decided that patents should, as a result of applying the test formulated in Aerotel/Macrossan, be allowed to protect a computer program if, but only if, the program implements a patentable invention," the UK-IPO said.
"This ruling is a narrow one which places a greater emphasis on the substance of what has been invented than the words used in the claim," the UK-IPO said. "It does not have the effect of making computer programs generally patentable in the UK but it does allow innovators to enforce all aspects of their patentable inventions directly."
The UK-IPO said it will not appeal the judgment and will be following it with immediate effect.
Links to further information:
A full copy of the Practice Notice can be viewed at http://www.ipo.gov.uk/patent/p-decisionmaking/p-law/p-law-notice/p-law-notice-subjectmatter.htm
2. A copy of the judgement in the cases Aerotel Ltd v Telco Holdings Ltd (and others) and Macrossan's Application  RPC 7 ("Aerotel/Macrossan") can be viewed at http://www.bailii.org/ew/cases/EWCA/Civ/2006/1371.html
3. A copy of the judgement (Astron Clinica's Application and others Applications  EWHC 85 (Pat) can be viewed at http://www.bailii.org/ew/cases/EWHC/Patents/2008/85.html.
4. What is patentable in the UK is determined by the Patents Act 1977 which is aligned with the European Patent Convention (EPC). Among other things, this states that patents are not available for computer programs as such.